lkml.org 
[lkml]   [2001]   [Jan]   [18]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: 2.4.1pre8 slowdown on dbench tests
On Thu, Jan 18, 2001 at 03:17:13PM -0200, Marcelo Tosatti wrote:
> Jens, can be the -blk patch the reason for the slowdown I'm seeing?

This heuristic is way too aggressive:

/*
* Try to keep 128MB max hysteris. If not possible,
* use half of RAM
*/
high_queued_sectors = (total_ram * 2) / 3;
low_queued_sectors = high_queued_sectors - MB(128);
if (low_queued_sectors < 0)
low_queued_sectors = total_ram / 2;

/*
* for big RAM machines (>= 384MB), use more for I/O
*/
if (total_ram >= MB(384)) {
high_queued_sectors = (total_ram * 4) / 5;
low_queued_sectors = high_queued_sectors - MB(128);
}

2/3 of ram locked down in the I/O queue is way too much. 1/3 should be ok. big
RAM machines needs way less than 1/3 locked down.

Marcelo can you give a try with `high_queued_sectors = total_ram / 3' and
low_queued_sectors = high_queued_sectors / 2 and drop the big ram machine
check?

Andrea
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2005-03-22 13:28    [W:0.164 / U:4.480 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site